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Laboratory criteria for diagnosis

Biologic: A case in which the whole blood cyanide concentration is elevated. Whole blood cyanide concentration can vary from 0.02 to 0.5 µg/mL in people without clinical manifestation of acute cyanide toxicity (3).

- OR-

Environmental: Detection of cyanide in environmental samples (4-7).

Case classification

Suspected: A case in which a potentially exposed person is being evaluated by health-care workers or public health officials for poisoning by a particular chemical agent, but no specific credible threat exists.

Probable: A clinically compatible case in which a high index of suspicion (credible threat or patient history regarding location and time) exists for cyanide exposure, or an epidemiologic link exists between this case and a laboratory-confirmed case.

Confirmed: A clinically compatible case in which laboratory tests have confirmed exposure.

The case can be confirmed if laboratory testing was not performed because either a predominant amount of clinical and nonspecific laboratory evidence of a particular chemical was present or the etiology of the agent is known with 100% certainty.